Olfaction and taste are central sensory modalities in host-seeking and mate recognition by mosquitoes. In collaboration with the laboratory of Larry Zwiebel we recently described the first few odorant receptor proteins from the major African malaria vector mosquito, Anopheles gambiae. With the release of the entire genome sequence of this mosquito I have worked up the entire insect chemo-receptor superfamily of 76-79 odorant receptors (AgOrs), which will be studied further in Larry Zwiebel's laboratory, and 76 gustatory receptors (AgGrs), which I propose to study with five specific aims. The first is to establish the expression patterns of all 76 AgGrs using RT/PCR and/or a chemosensory micro-array, paying particular attention to AgGrs with sex-specific expression patterns. Expression patterns will be confirmed with polyclonal antibodies generated against the most interesting subset of AgGrs. Secondly, we will examine the developmental profiles of the most interesting AgGrs identified. Thirdly, we will study the regulation of expression of female-specific AgGrs after a blood meal, testing the hypothesis that if they are involved in host seeking they should be down regulated after a blood meal. Fourth, we will examine the molecular evolution of a subset of interesting sex-specific AgGrs to look for those that are rapidly evolving. Finally, we will undertake ligand specificity studies of a few AgGrs to test hypotheses about their ligands generated from the first four aims. These will involve heterologous expression in Drosophila and/or RNA interference in mosquitoes, followed by neuro-physiological recordings and/or behavioral tests. The Or and Gr gene families have only been recognized with the sequencing of the A. gambiae genome, so these are studies that simply could not have been undertaken without the genome sequence, indeed to take full advantage of the genome sequence it is important that previously elusive gene families like these with central importance to the biology of mosquitoes and their transmission of disease be studied. These studies will greatly enhance our understanding of chemoreception in mosquitoes, which are major vectors of human and animal diseases. An improved understanding of mosquito chemoreception at the molecular level might provide insight and tools for development of novel attractants and/or repellents. This work will also contribute to our overall understanding of the molecular basis of chemoreception in insects and other animals. [unreadable] [unreadable]